Reel stands

ABSTRACT

A reel stand for supporting reels on which can be wound webs of paper, metal foil, polythene film or like material, comprises a pair of supporting arms between which two reels are supported for independent rotation about a common axis, while webs are drawn from the reels simultaneously and a web-tensioning system incorporating an arrangement common to the webs for monitoring the web tension and producing a controlled output dependent on the combined tension in the webs. Each reel has a tension strap which engages its peripheral surface, and a control arrangement responsive to the monitoring arrangement is arranged to vary the tension in the straps, each strap being associated with a cam over which the strap passes and which is arranged to modify the tension applied to the strap by the control arrangement.

United States Patent Primary Examiner-Stanley N. Gilreaflh Assistant Examiner-Werner H. Schroeder Attorney-Kirschstein, Kirschstein, Ottinger & Frank ABSTRACT: A reel stand for supporting reels on which can be wound webs of paper, metal foil, polythene film or like material, comprises a pair of supporting arms between which two reels are supported for independent rotation about a common axis, while webs are drawn from the reels simultaneously and a web-tensioning system incorporating an arrangement common to the webs for monitoring the web tension and producing a controlled output dependent on the combined tension in the webs. Each reel has a tension strap which engages its peripheral surface, and a control arrangement responsive to the monitoring arrangementis arranged to vary the tension in the straps, each strap being associated with a cam over which the strap passes and which is arranged to modify the tension applied to the strap by the control arrangeannssranns This invention relates to reel stands for supporting reels on which are wound webs of paper, metal foil, polythene film or other like materials, hereinafter referred to simply as paper, while a web of paper is drawn therefrom into a processing machine such as a printing press or associated equipment, such reel stands normally being provided with means for automatically controlling the tension in the web as it is drawn from a reel; said web tension control means may comprise, for example, a plurality of tension straps disposed so as to frictionally engage the peripheral surface of the reel, and means for controlling the pressure of the straps in dependence upon the tension in the web, so as to maintain the web tension substantially constant.

For some applications it may be convenient or desirable to support two or more reels of less than the full width on the same spindle arms of the reel stand and draw webs from each of these reels simultaneously. For example it could be convenient to feed a plain web and a partially preprinted web, each of approximately half the normal full width, simultaneously from the reel stand into a printing press. However in order to do this it has hitherto been thought necessary to include a separate automatic web-tensioning control system for each web, which adds considerably to the cost of the equipment.

' According to the present invention a reel stand comprises means for supporting two or more reels for independent rotation about a common axis between a pair of reel supporting arms to permit webs to be drawn from the reels simultaneously, and a web-tensioning system incorporating means common to the webs for monitoring the tension therein and for producing a controlled output dependent upon the combined tension in the webs, at least one tension strap designed to engage the peripheral surface of each reel, and control means responsive to the output of the monitoring means and ar ranged to vary the tension in the strap, each of said straps being associated with a respective cam over which the strap passes, and which is arranged to be actuated so as to modify the tension applied to the respective strap by the control means.

The cams which may be supported for pivoting movement in response to the control means are thus arranged to provide a variable ratio between the tension applied by the control means and that imparted to the strap at the reel, and such a control arrangement can be utilized to provide satisfactory control of the tensions in the webs drawn simultaneously from two or more reels, despite differences in the reel diameters, using a single common monitoring unit.

Each cam is so arranged that the tension applied to the associated strap compared with that applied to the control means is proportionately smaller when the respective reel is at its maximum diameter than when the reel is at its minumum diameter, considering that the angle of wrap of the strap around a reel varies with reel diameter.

The reel stand may incorporate a twoor threeor more armed spider, consisting of two spaced members each provided with one, two or three, or more pairs of aligned support arms between which the reels can be mounted; a shaft may, for example, extend between corresponding support arms on the two spider members, and carry first and second reel supports which are independently rotatable about the shaft and are designed to locate and support a first and second reel respectively; alternatively the shaft may itself be rotatable and carry means for locating and supporting a first reel, and further means rotatable with respect to the shaft for locating and supporting a second reel.

The automatic tensioning system is also suitable for controlling the tension in a single web drawn from a reel extending across the width of the reel stand, and a reel stand in accordance with the invention designed for supporting two or more reels can thus readily be modified for use with a single full width reel by replacement of the reel supporting arrangement. Similarly a reel stand primarily designed for use with a full-length reel and having a tension control arrangement of the form described can be quickly modified for use with two or more relatively narrow reels without the expense of installing a separate tension control system for each web.

The means for monitoring the web tension conveniently includes a common roller over which the webs are arranged to pass, and pivoted about an axis offset from, but parallel to the roller axis, the roller being biassed against the tension in the webs, for example by fluid pressure or by one or more springs, and being coupled to a monitoring unit the output of which is designed to vary in dependence upon the position of the roller. The monitoring unit may for example be arranged to control the pressure of a fluid supplied to piston and cylinder units arranged to vary the tension in the respective tension straps.

Reel stands carrying two or more reel-supporting arms are commonly provided with means for rotating the reel support to bring a replacement reel into the running position when the web on the running reel has nearly expired, and are associated with means for severing the expiring web and joining the end of the new web to the severed end of the expiring web when the replacement reel has been run up to the appropriate speed.

A reel stand in accordance with the invention carrying two or more running reels may similarly be associated with means for joining new webs to the ends of expiring webs and provided the diameters of the two or more replacement reels are within predetennined limits in respect to. each other, and likewise, though to a far lesser extent, the expiring reels, it is possible to effect the joining of the reels simultaneously provided that the necessary. preparations at the ends of the webs are similarly positioned with respect to each other on the reel surfaces; moreover such simultaneous joining may in many cases be effected by means of joining equipment designed primarily for use with single running reels, without any appreciable change in its construction.

One embodiment of the invention will now be described by way of example with reference to which FIGS. 11 and 2 represent in diagrammatic form and not to scale a side view and an end view of the reel stand, and

HO. 3 represents an enlarged section through a suitable reel support.

Referring to the drawings the reel stand it comprises a threearmed spider 2 comprising two spaced members 3 (FIG. 2) mounted on a common shaft 4 and each having three support arms 5 for supporting running reels and replacement reels. The spider is capable of being rotated in known manner to bring a replacement reel Rll into the running position R2 when the web on the running reel has nearly expired, means (not shown) of any suitable kind being associated with the reel stand for severing the expiring web and joining the end of the new web to the severed end of the expiring web when the replacement reel has been run up to the appropriate speed.

The reel stand l is designed to support either one full or fractional width reel, or alternatively two fractional width reels between each pair of anns of the spider 2, and for the latter purpose is provided with a multiple spindle as at 8 (FIG. 3). This comprises 5 central tubular reel support tube ill provided at its ends with bung adapters 12 designed to fit over rotatable bungs 13 carried by corresponding arms 5 of the spider support members 3 so that the tube is free to rotate. One half of the tube ll is fitted with a pair of spaced sleeves 14 each of which supports, by means of bearings 15 of any suitable form, a freely rotatable collar 16, the collars being arranged to fit into the ends of, say, a preprinted reel 17. The other half of the shaft 11 carries two further collars l8 fixed in position and designed to be fitted into the end of, say, a totally unprinted reel W, the two reels thus being independently rotatable about a common axis.

The webs from the reel are arranged to pass over a system of rollers 211, 22, 23 (FIG. 1), the roller 22 being mounted on pivotable arms 2d fixed to a shaft 25. This shaft is coupled to a lFlGS. l to 3 of the accompanying schematic drawing, in

monitoring unit M of any convenient kind designed to produce an output dependent upon the combined tensions in the webs from the two reels 17, 19.

The reel stand also includes a web tension control arrangement responsive to the output of the monitoring unit. This comprises four tension straps 26 two of which are associated with the reel 17 and the other two of which are associated with the reel 19. One end of each strap is anchored to a suitable fixed anchoring point 27 and is arranged to wrap partly around the periphery of the respective reel before passing to an associated cam 28, the cams being independently rotatable about a horizontal axis 29.

The other end of each strap 26 is attached to the cam 28 in such a manner that rotation of the cam about its axis in one or other direction wraps or unwraps the strap 26 on the cam surface. A drive pulley 31 is rigidly secured to one side of the cam and a further strap 32 is attached to pulley 31 in such a manner that when the tension strap is wrapped further on to the cam the further strap 32 is unwrapped from the pulley 31 and vice versa. The opposite end of the strap 32 passes round a further pulley 33 which is carried by the piston 34 working within pneumatic cylinder 35 which constitutes the strap-tensioning device.

The monitoring unit M conveniently comprises a piston and cylinder unit 44 having its piston connected to one end of an arm 46 fixed at approximately its center to one end of the shaft 25. In use of the apparatus air at a preselected controllable pressure is supplied to the piston and cylinder unit 44 in such a sense as to urge the arm 46, and hence the arms 24, in the direction (counterclockwise in FIG. 1) which opposes and counterbalances the combined web tension forces acting on the roller 22. There is also provided a variable'output-pressure, lever-operated, valve 45 fed from a constant pressure source, the operating level of the valve being also coupled to the arm 46 so that the output pressure is proportional to the angular position of the arm and roller assembly 46, 24, 22 which will vary as a result of variation in web tension. The output pressure'of the valve 45 is applied to each of the piston and cylinder units 34 and 35, to provide the desired control of the web tension straps 26, in such a sense as to compensate for such web tension changes and thereby maintain the web tensions substantially constant.

Although the webs share a common monitoring unit the action of the cams, which are arranged to modify the tension in the respective tension straps in dependence upon the associated reel diameter, enables adequate control of the tension in both webs to be obtained even though the reel diameters may differ.

In some cases means may be provided for adjusting either the reel 17 or 19 relative to the complete assembly so that the axial spacing between the inner edges of the two reels can be kept substantially constant with successive reels to ensure that lateral register is maintained. To this end, as shown in FIG. 3, the axially innermost of the sleeves 14 is provided with an externally threaded boss 14A which screws into an internally threaded extension 18A on the adjacent collar 18. Rotation of the unprinted reel 19 relative to the shaft 11 increases or decreases the axial spacing between the reels 17 and 19 depending on whether the direction of rotation is such as to screw or unscrew the cooperating threads on the boss 14A and the extension 18A. When the required axial spacing is obtained, the unprinted reel 19 is locked to the shaft 11 by locating a key 188 on the other collar 18 in a keyway in the unprinted reel 19 and locking the collars 18 to the shaft 11.

The reel stand can readily be modified for normal use with a single full or fractional width reels by replacement of the multiple spindles 8 by the usual reel supports capable of accommodating the full or fractional width reels, the running reel then being engaged by the appropriate number of straps 26, according to reel width, of the web tension control arrangement.

We claim:

1. A reel stand comprising: a. means for supporting at least two reels for independent rotation about a common axis between a pair of reel supporting arms to permit webs to be drawn from the reels simultaneously;

b. a web tensioning system incorporating means common to the webs for monitoring the tension therein and for producing a controlled output dependent upon the combined tension in the webs;

c. for each reel at least one tension strap and an associated cam, the cams associated with the different reels being independently rotatable, and each strap being engageable with the peripheral surface of the respective reel and passing over the respective cam, and

d. for each cam, a separate control means responsive to the output of the common monitoring means and coupled to the cam to apply a turning force thereto, in dependence upon the output of the monitoring means, which tensions the respective tension strap, thereby controlling the tension in the web drawn from the respective reel, the distance of the active part of the surface of each cam from its axis decreasing as the cam is rotated in a direction to tighten the strap against the reel, thereby increasing the tension in the strap for a given applied turning force, and compensating for changes in the respective reel diameter.

2. A reel stand as claimed in claim 1, incorporating a spider consisting of two spaced members each provided with at least two pairs of aligned reel supporting arms between which the reels can be mounted.

3. A reel stand as claimed in claim 1, wherein a shaft extends between each pair of reel supporting arms and each shaft carries first and second reel supports which are independently rotatable about the shaft and which carry the reels.

4. A reel stand as claimed in claim 1, wherein a rotatable shaft extends between each pair of reel supporting arms and carries means for locating and supporting a first reel and further means rotatable with respect to the shaft for locating and supporting a second reel.

5. A reel stand as claimed in claim 1, wherein the means for monitoring the tension in the webs includes a common roller over which the webs are arranged to and which is pivoted about an axis offset from, but parallel to, the roller axis, the roller being biased against the tension in the webs and being coupled to the monitoring unit the output of which is designed to vary in dependence upon the position of the roller.

6. A reel stand as claimed in claim 5, wherein the monitoring unit is arranged to control the pressure of a fluid supplied to a piston and cylinder unit arranged to vary the tension in the respective tension straps.

7. A reel stand as claimed in claim 5, wherein the common roller is biased against the tension in the webs by an arrangement operated by fluid pressure.

8. A reel stand as claimed in claim 1, including means for adjusting the spacing between the reels in an axial direction.

9. A reel stand as claimed in claim 8, wherein the means for adjusting the axial spacing between the reels includes a screw thread arrangement adjusted by relative rotation of the reel mountings.

10. A reel stand as claimed in claim 1, wherein the tension straps are attached to the cams in such manner that rotation of the cams about their axis in one direction wraps the straps on the cam surfaces and rotation in the other direction unwraps the straps from the cam surfaces.

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1. A reel stand comprising: a. means for supporting at least two reels for independent rotation about a common axis between a pair of reel supporting arms to permit webs to be drawn from the reels simultaneously; b. a web tensioning system incorporating means common to the webs for monitoring the tension therein and for producing a controlled output dependent upon the combined tension in the webs; c. for each reel at least one tension strap and an associated cam, the cams associated with the different reels being independently rotatable, and each strap being engageable with the peripheral surface of the respective reel and passing over the respective cam, and d. for each cam, a separate control means responsive to the output of the common monitoring means and coupled to the cam to apply a turning force thereto, in dependence upon the output of the monitoring means, which tensions the respective tension strap, thereby controlling the tension in the web drawn from the respective reel, the distance of the active part of the surface of each cam from its axis decreasing as the cam is rotated in a direction to tighten the strap against the reel, thereby increasing the tension in the strap for a given applied turning force, and compensating for changes in the respective reel diameter.
 2. A reel stand as claimed in claim 1, incorporating a spider consisting of two spaced members each provided with at least two pairs of aligned reel supporting arms between which the reels can be mounted.
 3. A reel stand as claimed in claim 1, wherein a shaft extends between each pair of reel supporting arms and each shaft carries first and second reel supports which are independently rotatable about the shaft and which carry the reels.
 4. A reel stand as claimed in claim 1, wherein a rotatable shaft extends between each pair of reel supporting arms and carries means for locating and supporting a first reel and further means rotatable with respect to the shaFt for locating and supporting a second reel.
 5. A reel stand as claimed in claim 1, wherein the means for monitoring the tension in the webs includes a common roller over which the webs are arranged to pass and which is pivoted about an axis offset from, but parallel to, the roller axis, the roller being biased against the tension in the webs and being coupled to the monitoring unit the output of which is designed to vary in dependence upon the position of the roller.
 6. A reel stand as claimed in claim 5, wherein the monitoring unit is arranged to control the pressure of a fluid supplied to a piston and cylinder unit arranged to vary the tension in the respective tension straps.
 7. A reel stand as claimed in claim 5, wherein the common roller is biased against the tension in the webs by an arrangement operated by fluid pressure.
 8. A reel stand as claimed in claim 1, including means for adjusting the spacing between the reels in an axial direction.
 9. A reel stand as claimed in claim 8, wherein the means for adjusting the axial spacing between the reels includes a screw thread arrangement adjusted by relative rotation of the reel mountings.
 10. A reel stand as claimed in claim 1, wherein the tension straps are attached to the cams in such manner that rotation of the cams about their axes in one direction wraps the straps on the cam surfaces and rotation in the other direction unwraps the straps from the cam surfaces. 